/*
 *  Copyright 2004 Clinton Begin
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.ibatis.common.jdbc.logging;

import com.ibatis.common.beans.ClassInfo;
import com.ibatis.common.logging.Log;
import com.ibatis.common.logging.LogFactory;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

/**
 * PreparedStatement proxy to add logging
 */
public class PreparedStatementLogProxy extends BaseLogProxy implements InvocationHandler {

  private static final Log log = LogFactory.getLog(PreparedStatement.class);

  private PreparedStatement statement;
  private String sql;

  private PreparedStatementLogProxy(PreparedStatement stmt, String sql) {
    this.statement = stmt;
    this.sql = sql;
  }

  public Object invoke(Object proxy, Method method, Object[] params) throws Throwable {
    try {
      if (EXECUTE_METHODS.contains(method.getName())) {
        if (log.isDebugEnabled()) {
          log.debug("{pstm-" + id + "} Executing Statement: " + removeBreakingWhitespace(sql));
          log.debug("{pstm-" + id + "} Parameters: " + getValueString());
          log.debug("{pstm-" + id + "} Types: " + getTypeString());
        }
        clearColumnInfo();
        if ("executeQuery".equals(method.getName())) {
          ResultSet rs = (ResultSet) method.invoke(statement, params);
          if ( rs != null ) {
            return ResultSetLogProxy.newInstance(rs);
          }
          else {
            return null;
          }
        } else {
          return method.invoke(statement, params);
        }
      } else if (SET_METHODS.contains(method.getName())) {
        if ("setNull".equals(method.getName())) {
          setColumn(params[0], null);
        } else {
          setColumn(params[0], params[1]);
        }
        return method.invoke(statement, params);
      } else if ("getResultSet".equals(method.getName())) {
        ResultSet rs = (ResultSet) method.invoke(statement, params);
        if ( rs != null ) {
          return ResultSetLogProxy.newInstance(rs);
        }
        else {
          return null;
        }
      } else if ("equals".equals(method.getName())) {
        Object ps = params[0];
        if (ps instanceof Proxy) {
          return new Boolean(proxy == ps);
        }
        return new Boolean(false);
      } else if ("hashCode".equals(method.getName())) {
        return new Integer(proxy.hashCode());
      } else {
        return method.invoke(statement, params);
      }
    } catch (Throwable t) {
      throw ClassInfo.unwrapThrowable(t);
    }
  }

  /**
   * Creates a logging version of a PreparedStatement
   * @param stmt - the statement
   * @param sql - the sql statement
   * @return - the proxy
   */
  public static PreparedStatement newInstance(PreparedStatement stmt, String sql) {
    InvocationHandler handler = new PreparedStatementLogProxy(stmt, sql);
    ClassLoader cl = PreparedStatement.class.getClassLoader();
    return (PreparedStatement) Proxy.newProxyInstance(cl, new Class[]{PreparedStatement.class, CallableStatement.class}, handler);
  }

}